- Fluoxetine administration - Participants will be randomly assigned to receive either 10 mg. of fluoxetine or placebo (identical capsules with no active ingredients) once a day for 3 days, then twice a day, increasing up to four capsules a day if there are no serious side effects. Blood will be drawn once a month to measure drug levels. At the end of 3 months, participants taking placebo may remain in the study and receive fluoxetine.